Conventionally, in the production of surface-mountable optoelectronic components, by way of example, firstly a prefabricated electrical leadframe is encapsulated by injection-moulding with a suitable plastics material which forms the basic housing of the component. This basic housing has a cavity (or else chip window) into which leadframe terminals are introduced from two opposite sides. A semiconductor chip that emits and/or transmits electromagnetic radiation, such as an LED chip, for example, is bonded and electrically contact-connected on one of the said leadframe terminals. A transparent or translucent potting compound is built into the cavity. This basic form of surface-mountable optoelectronic components is disclosed for example in the article “SIEMENS SMT-TOPLED für die Oberflächenmontage” [“SIEMENS SMT-TOPLED for surface mounting”] by F. Möllmer and G. Waitl, Siemens Components 29 (1991), issue 4, pages 147-149.
In the case of such optoelectronic components, it is customary, for the purpose of increasing the external efficiency, to form the cavity with oblique inner areas which serve as reflector. Depending on the angle of inclination of the inner areas, the opening of the cavity is correspondingly enlarged thereby.
Examples of optoelectronic components with such reflector arrangements are disclosed for example in the document DE 197 55 734 A1 and the document DE 199 18 370 A1.
A similar construction is described in the document DE 195 36 454 A1. In this case, a metal chip carrier part on which the semiconductor chip is mounted is provided in a cavity of a basic housing of the component. A well is formed in the chip carrier part in the region in which the semiconductor chip is fixed, the inner areas of which well approximately correspond to the form of an inverted truncated cone and form a reflector for the radiation emitted by the semiconductor chip.
Advancing miniaturization of optoelectronic components entails more and more often the requirement for the narrowest possible openings of the cavity and/or for more complex semiconductor chip and wiring arrangements in the cavity. In these cases, for lack of space, the side walls of the cavity can often only be formed perpendicularly or at a steep angle with respect to the bottom area of the cavity.
The usually Lambert or even rearwards directed radiation or reception characteristic of the semiconductor chip means, therefore, that significant losses of luminous flux arise and a lower external efficiency of the component thus arises. Therefore, there is a need for optoelectronic components which have a sufficiently good efficiency despite the absence of reflectors, or reflectors that cannot be realized, at the inner areas of their cavities.